This invention relates to an elastic mold used for producing a molded product by charging a fluidized molding material therein and extracting a solidified molded product therefrom and a method for producing a molded product using the elastic mold.
It has been known to use an elastic mold of rubber or synthetic resin for mass-producing molded products having three-dimensional portions on their surfaces such as chocolate cakes or ice creams from a fluidized molding or charging material. Such elastic mold is composed of a product molding section for duplicating a molded product and a holding section for securing the mold to a production device. The fluidized charging or molding material is charged into the mold and solidified to form a molded product, and the elastic mold is then expanded to extract the molded product from the mold.
A typical production device for producing such charged molded product using such elastic mold is disclosed in, for example, Japanese Laid-open Patent Application No. 63-31726 (1988). The production device is composed of a unit for charging a molding material into an elastic mold in the shape of a pouch opened at one end having a three-dimensional portion such as an animal, a unit for solidifying the charged molding material and a unit for extracting the solidified material by expanding the mold under reduced pressure.
Referring to FIG. 9, a pattern for molding 50 for producing the conventional elastic mold is comprised of a three-dimensional main portion 52 and a flat portion 51 connected thereto via a transition zone presenting an acute bend. Thus, when the pattern for molding 50 is immersed in a solution 30 of an elastic material contained in a container 40 for forming a thin membrane around the pattern for molding 50, an elastic mold 20 as shown in FIG. 8 is produced, in which a membrane thickness is increased on the outer side of a take-out opening 13 at a boundary between a product molding section 11 and a mold holding section 12.
When extracting a molded product 60 from the above mentioned conventional elastic mold 20 as shown in FIGS. 10 to 12, the elastic mold 20 having its mold holding section 12 secured to a belt conveyor of a production line (not shown) is transferred to a pressure-reducing chamber 35. First, the pressure-reducing chamber 35 is evacuated as indicated by an arrow in FIG. 10 for increasingly expanding the elastic mold 20 as shown in FIGS. 11 and 12. However, as shown in FIGS. 11 and 12, the take-out opening 13 of the elastic mold 20 cannot be expanded sufficiently because of its increased membrane thickness, so that the molded product cannot be extracted from the mold smoothly. In addition, uniform expansion cannot be achieved because of the difference in membrane thicknesses, thus giving rise to distortions and detracting from durability of the elastic mold.